1. Field of the Invention
The present invention generally relates to a light source device; particularly, the present invention relates to a light source device that has an external lens.
2. Description of the Related Art
Within various technical fields, especially to the field of display technology and illumination equipments, the design of light sources has always been an important aspect of light sources. Conventional light sources typically utilize light bulbs or incandescent tubes as light sources. As the technology of light-emitting diodes (LED) has matured and since LEDs have advantages of being small and being environmentally friendly by saving energy, LEDs have gradually become a mainstay on the market.
In order to increase the illumination area in practical usage, the conventional light source as shown in FIG. 1 has a lens 10 disposed and covering on top of a light-emitting diode chip 30. As shown in FIG. 1, an empty cavity 11 is formed within the lens 10 to accommodate the light-emitting diode chip 30. The top of the lens 10 forms a recess 13 that is directly above the light-emitting diode chip 30. In this design, the angle at which light is emitted is determined by an outer surface 15 of the lens 10 so that a relatively larger light-emitting area may be obtained.
However, the distribution of light produced by the above design will typically form ring shaped areas of strong light. In other words, the light will not be smooth. In addition, since the light-emitting diode chip 30 is completely covered within the cavity 11, there will be heat dissipation problems.